Feeding mechanism



April 13, 1943. F. E ,s`lNcLAlR FEEDING MECHANISM Filed July 16, 1940Patented Apr. 13, 1943 UNTTED STATES PATENT OFFICE 2,316,192 1 FEEDINGMECHANESM Frank E. Sinclair, Claremont, N. H., assigner to SullivanMachinery Company, a corporation of Massachusetts Application July 1e,1940, serial No. 345,795 140mm. (C1. 25e-45) My invention relates tofeeding mechanisms, and more particularly but not exclusively to feedingmechanisms for rock drills of the socalled air-feed drifter type.

vIn rock drills ofthe so-called air-feed drifter type, rock drillingmotors are commonly slida'blt7 guided for reciprocatory feeding andretracting -movements along guide shells or their equivalents, and areprovided with means actuated by air motors for effecting such oppositemovements.

Power for feeding and retraction may =be derived either from thedrilling motor or a separate mo- Y tor. A very satisfactory mechanismfor. effecting such movements comprises a longitudinally fixed feedscrew rotatable in opposite directions at the'steel, having set the feedmotor` in reversel rotation, beV distracted or turn their attentionelsewhere, with the result that the feednut may be moved to the rearwardlimit of possible motion and the parts may become jammed, this beingeasily possible because the load during re-` traction is usually smalland the power of the Vfeed may be considerable, so that when therearward limit of feed is reached `a wedging action takes place betweenthe rotating and the stationary parts, with the resultant bother andnuisance of having to free the parts. Moreover,

`it is not impossible that some damage may be occasioned by the sudden`stoppage of the parts which have been previously in relatively freemovement. It will be appreciated that similar difficulties may also attimes be encountered at the forward limit of feed, and that Vwithautomatic jump feeds, and even with manual feeds,

(analogous, though less serious, difficulties may be met. Y i

Ina preferred embodiment of my invention it .may include relativelyrotatable feeding elements, a source of power for turning one of saidelements, thereby to cause a feeding or retract- 'ging movement of oneof said elementaimeans for building up a load progressively as a memberof such means is moved, and means for causying the movement of thefeeding element last mentioned to effect, automatically, when a limit offeed is approached, a connection whereby said power-turned elementeffects a load-increasing movementof said member. Desirably, but notnecessarily, the `source of power may be separate from thework-performing motor when a workperforming motor is the device to befed. In some cases the hammer motor itself may constitute the source ofpower; and the feed may be effected by jumping action of the hammer`motor, or by power drive of the rotatable feeding element through asuitable driving lmechanism. Even manual rotation ofthe screw isincluded within the purview of the invention. Desirably, but notnecessarily, a torsion spring coupleable for winding up by thepower-turned `feeding element may beutilized as the source of increasingresistance to the turning of said power-turned element. Other aspectsand phases of the invention will hereinafter appear.

It is an object of my' present inventionto provide `an improved meansfor avoiding the difficulty mentioned. It is another object of myinvention -to provide an improved feeding mechanism fora rock drillingmotor.v It is a further object 'of my invention to provide an' improved`means for bringing to a stop, without harmful V'sliock,and withoutVsticking or'jamming of the parts, the moving hammer motor of a power-feddrifter, in the event that` the operator fails to turn off at aseasonable time the motorwhich is effecting feeding movement. It isanother object of my invention to provide an improved .means forautomatically checking feeding movement at either end of the travel'of adrifter drill, regardless of the type of feed used, before stickingoccurs. It isrstill another object of my invention to provide animproved feeding mechanism for an air-feed hammer motor or other workingtool, having improved means incorporl ated therein for storing `energyto facilitatethe initiation of a reversal of a feeding movement, whileat theA same time automatically interrupting,.without damage orsticking, a feeding movement which is not seasonably stopped `by thedrill runner." Yet another object of my invention is to provide animproved feed-checking apparatus of general application to anymotor-operated or other comparable-problem-presenting feeding mechanismfor moving a part to fbe fedgrelative' to a fixed limit. Otherobjectsand 'advantages of the invention will hereinafter more fullyappear. ,Y

In the accompanying drawing, in which for purposes of illustration oneembodiment of the invention is disclosed:` I

Fig. 1 is aside. elevation,

with lparts broken away, of a so-called air-feed drifter in which theinvention in its illustrative form is incorporated. Fig. 2 is a somewhatenlarged view, with parts shown in elevation but mainly in centralvertical longitudinal section, through the feeding mechanism of theapparatus shown in Fig. 1.

Fig. 3 is a view generally similar to Fig. 2 but omitting some of theparts shown in Fig. 2, and with some of the parts which appear in bothfigures in different relative positions in Fig. 3 from those of Fig. 2.

Fig. 4 is a transverse section on a somewhat enlarged scale on the planeof the line 4*--4 of Fig, 2.

Fig. 5 is a transverse section on a somewhat enlarged scale on the planeof the line Ve-Ei of Fig. 2.

Fig. 6 is a transverse section on a somewhat l enlarged scale on theplane of the line S- of Fig. 2.

Fig. 'l is a section on the plane of the line l-l of Fig. 4, through aclutch element. I

Referring now to the drawing, it will be noted that a hammer motor I,which is adapted percussively to a-ctuate a drill steel 2, is mountedfor sliding movement in a guide shell 3. The motor I has a depending lug4 at its rear end in which a feed nut 5 is received, said feed nut beingvclamped in position by means of a washer 6 and a holding nut 'I at therearward end of the lug 4, and the feed nut having, at its forward end,a head 8 spaced by another washer 9 from the lug 4, The feed nut isadapted to cooperate with a feed screw II. The feed screw II isprovided, at its rear end, with an enlarged circertain of the cylindersbeing shown at 2), 2li, 2B.

The motor I'I .is reversible, and a'handle 2l is movable, hereinarcuately, between opposite eX- treme positions in which forward feedand retraction are respectively effected, the feeding motor being shutvdown completely in an intermediate position of the handle 2|. A motor1power shaft is shown at 22, and this is connected l through a suitabletongue and slot connection 23 to drive the rear end of the feed screwIt. The forward end of the feed screw may be journaled in any suitableway, as at 2li, at or adjacent the forward end of the shell 3. The feedscrew is of course held against longitudinal movement relative to theshell 3, and accordingly its rotation in one direction will cause thefeed nut 5, which is fixed non-rotatably in the lug Ii, to movelongitudinally of the guideways of the shell 3 and so effect movement ofthe hammer motor I in one direction.l Movement of the hammer motor inthe opposite direction will, of course, be occasioned by the reverserotation of the feed screw II Now, if the drill runner moves the handle2l to a position to effect forward feed and supplies air under thecontrol of a throttle valve mechanism 25 to the hammer motor I, thedrill steel 2 may be caused to drill a hole. Because during the drillingoperation the operator will be giving the apparatus close supervision,and because the rate of forward feed is comparatively slow, and vbeofthe parts.

member d I'.

asiatica cause Vthe operator will be continuously on the Watch for thepoint where steel change is to be effected when reached, there is littleprospect of jamming the feed during the forward feeding operation. When,however, the desired limit of forward feed has been reached and thedrill is being retracted, the feeding movement will be much more rapid,and frequent sticking of the parts and undesirable shocks due to themotors feeding back to the rearward limit of its feed, would occur wereno means for guarding against this difficulty provided. I have provided,to avoid this diculty, a mechanism adapted to build up an increasingresistance to rotation of the feed screw as the hammer motor approachesthe rearward limit of its travel; a mechanism which will store energywhile bringing the feed screw to a stop, which energy will be availableto initiate the opposite movement ofthe feed screw, and which mechanismis desirably, though this is not necessary in View of the energy-storingfeature, adapted to preclude al frictional locking At this point itshould be noted that there is no reason why similar mechanism may not beprovided at the front end of the shell if desired.. Itwill be noted thatthe locking nut "I is provided with a somewhat elongated rearwardcylindrical portion 35 which is of a size to enter an opening 3-I in athreaded sleeve member 32, which is screwed into an internally threadedprojecting portion 32 on the forward member 35 of the housing I. Theopening 3| is of somewhat smaller diameter than the internal cylindricalbore 31 which is formed within the member 32. Within the bore. 31 andbetween the inwardly turned flange 33 which surrounds the opening, 3|and a shoulder 39 formed by an inwardly extending flange on the headmember 35, there are arranged a stop element in the form of a clutchmember 4I and a helical spring 42 of the torsion type. The rearward Yendof the spring 42 has a tang 43 which is received in a recess. i4 formedin the flange 39. The forward end of the spring has a tang received in arecess or notch 5I in the clutch The clutch member' il is cut away, asat 52, so as to permit it to be' positioned, when the housing member* 32is unscrewed from its mounting, over the feed screw member II in theproper position,

The portion of the feed screw member I I within the bore 3l is providedwith a series of longitudinally extending tooth-like portions 54 whoseforward ends are slanted, as at 55, somewhat more steeply than the leadof the feed screw. The clutch member Il is provided with corre'-sponding tooth or spline-like portions 56, having sloping rearward ends51. YIn the position of the parts Vnormally occupied, that shown in Fig.2, the teeth 54 and 56 are disengaged. In the position shown in Fig. 3they are engaged and all rotation of the feed screw is attended byrotation of the clutch member 4I.

The spring l2 may be made of different strengths, but I prefer to makeit of such dimensions and strength that the amount of power required towind it up will be such that the feeding motor will be brought to a stopby the increased load before the spring is fully wound up into contactwith the outside of the teeth 54, and before the spring is compressedlongitudinally sufficiently to bring its successive turns into lateralengagement. And the length ofl the portion 32 will be made suflicient sothat there I pended claims..

will be no engagement between the member 32 and tne nut l before themotor 'is stopped.

-also be true during thenormal range of retraction. But if the operatorfails to stop the feeding motor seasonably and the hammer motor tends tomove so far back that there would be danger of jamming the parts, theprojection 3D will enter the opening 3| and engage the `clutch member4|.

As the clutch member, 4| is forced to the left in Figs. 2 and 3, itsslopingtended teeth 5B will .engage with Vthe teeth-54 on the feed screwmember and slide rearwardly between the latter teeth. As soon as suchengagement occurs, the clutch member 4| will The only parts betweenwhich substantial frictional binding may occur will be between the rearend of the feed nut and the holding nut 30, on the one hand,v and theclutch member 4|, but this will be easily overcome by the stored energyin the spring 42, and if desired an antifriction bearing can be providedto transmit the thrust from the feed nut to the clutch member 4| and soeliminate even the binding mentioned.

It will be evident from what has been said that I have provided a devicewhich will effectively prevent breakage and jamming of the parts if theretraction is not seasonablyinterrupted by the' drill runner; that theparts are simple and Yrugged and require very little` modification fromDuring `forward feed- 2- respectively, said elements in engagement witheach other and operative on relative rotation to effect movement of`said tool along said guiding and supporting means, a motorfor rotatingone of said elements, and means for automatically imposing on said motoran additional load suf- -cientto stop tool movement as said toolapproaches an end of its travel on said guiding and supporting means,said load-imposing means including a stop elementv rotatable about an#axis and with which an element of said workperforming tool isengageable and resilient means forY resisting rotary` movement of saidstop element. l

l2. In combination, a Work-performing tool, guiding and supporting meanstherefor along which said tool is adapted to be fed during feedingtowards and retraction from the work, relatively rotatable elementsmounted on said tool and on said guiding and supporting meansrespectively, said elements in engagement with each other and operativeon relative rotation to effect movement of said tool along saidguidstandard parts which lack the advantages of the present invention;and that if the `refinement available to prevent any frictional bindingwhatever is not considered warranted,`for any reason, the energy storedin the spring will be in any event more than adequate toinsure immediateinitiation of forward feed when the lever'2l is moved to forward feedposition. It is to be observed also, as above pointed out, that the useof such a device is not limited to the `type of feed shown, or to therearward end of the feed screw. l Y Y While I have in this applicationspecifically' described one form which my invention may ,assume inpractice, it will be understood that this form is shown for purposes ofillustration and that the invention may be modied and iembodied invarious other forms without departing from its spirit or the scope ofthe ap- What I claim as new and desire to secure by Letters Patent is:

1. In combination, a work-performing tool,

, guiding and supporting means therefor along `which said tool isadapted to be fed during feedandmon lsaidnguiding and supporting-means,

ing and supporting means, a motor for rotating one of said elements, andmeans for automatically imposing on said motor an additional load,increasing as tool movement continues, as said tool approaches an end ofits travel on said guiding and supporting means, said load-imposingmeans including a stop element having limited rotary motion and actuatedby an element of said work-performing tool and resilient means forresisting rotary motion of said stop element.

3. Incombination, a Work-performing tool, guiding and supportingmeansfor said tool, motor-operated feeding means for said tool includinga motor-rotated element and an element with which said motor-rotatedelement is engaged,

saidelements so disposed and engaged in such manner that rotation ofsaid motor-rotated element causes movement, longitudinally of said,

guiding and supporting means, of one of said elements, saidwork-,performing tool having said last mentioned element connectedthereto so,` that such longitudinal movements of said element areattended by movements of said tool longitudinally of .said guiding andsupporting means, and means for precluding overtravel of said tool finone direction including a spring coaxial with saidmotor-rotated elementand means for increasing the tension in said spring as the limit oftravel in such direction is approached, said spring tension increasingmeans including a rotary stop element which is engageable by an elementof said Work-performing tool.

4. In combination, a work-performing tool, "guiding and supporting meansfor said tool, mo-

nected thereto so that such longitudinal movements of said element areattended by movements of said tool longitudinally of said guiding andsupporting means, and means for precluding overtravel of said tool inonevdirection Aincluding a spring` fixed at one end and means for movingthe other end of said spring in a direction to increase the tensionthereof as the limit of -travel insuch direction Vis approached,

said spring tension increasing means including a stop element engageableby an element of said work-performing tool and having limited rotarymotion, said spring opposing the rotary motion of said stop element.

5. In combination, a work-performing motor, a. guidewjay along whichsaidv motor is reciprocabie towards and from its Work, a feed 'screwextending longitudinally of .said guideway, a feed nut carried by saidwork-performing motor, motor-operated driving means for said feed screw,a torsion spring surrounding said feed screw and 4having one `endthereof fixed, an element relative to which said feed scr'evvis normallyrotatable and which is movable longitudinally of said feed screw and towhichthe other end of said spring is fixed, means operative on movementof saidelement longitudinally of said screw inrone direction foreffecting clutching of said element to said screw,y whereby subsequentrotation of said screw Will effect Winding up of said spring, and meansmovable with said motor for effecting movement of said element intoclutched engagement with said screw.

- 5. In combination, a work-performing motor, a guideway along whichsaid motor is reciprocable towards and from its work, a feed screwextending longitudinally of said guideway, a feed nut carried by saidwork-performing motor, motor-operated driving' means for said feedscrew, a torsion spring surrounding' said feed screw and having one `endthereof fixed, an element relative to which said .feed screw isYnormally rctatableand which is movable longitutinally of said feedscrew and to which the other end of said'spring is fixed, meansincluding clutch teeth on said screw and cooperating clutch teeth onsaid element operative on movement of said element longitudinally ofsaid screw in one direction for effecting clutching of said Velement tosaid screw, whereby subsequent rotation of said screw will effectwinding up of said spring, and means movable with said motor for eectingmovement of said element into clutched engagement with said screw.

'7.In combination, in a feeding mechanism, a feed screw, a feed nut,motor-operated means for turning said feed screw in opposite directionsat wiil,and means actuated automatically on movement of said feed nutpast a predetermined point in one direction for imposing on said feedscrew a resistance to rotation progressively increasing as such movementof said feed nut continues, said resistance-imposing means includingstop means having limited rotary motion and resilient resistance meansfor priogressively increasing the resistance to rotary motion. of saidstop means as said feed nut passes said predetermined point.

8. In combination, in a feeding mechanism, a feed screw, a feed nut,means for turning said feed screw, and means actuated automatically onmovement of said feed nut into a predetermined relation to an end ofsaid feed screw for imposing on said feed screw an increasing resistanceto rotation, while the feed nut is still free to move, until theresistance to screw rotation exceeds the torque on the screw, saidresistance-imposing means embodying stop means having limited rotarymotion and resilient means for increasingly opposing rotary motion ofsaid stop means as said feed nut moves into said predetermined relation.

9. In combination, a work-performing tool, guiding and supporting meanstherefor along which said tool is adapted to be fed during feedingtowards and retraction .from the work, relatively rotatable elementsmounted on said tool and on said guiding and supporting meansrespectively, said elements in engagement with each other and operativeon relative rotation to effect movement of said tool along said guidingand supporting means, a motor for. rotating one of said elements, andmeans for automatically imposing on said motor an additional load assaid tool approaches an end of its travel on said guiding and supportingmeans, said load-imposing means including a torsion spring andcooperating means actuated by said motor-rotated element for winding upsaidrspring as said ytool approaches Vsaid end of lits travel;

l0. In combination, a work-performing tool, guiding and supporting means'therefor along which said tool is adapted to be fed during feedingtowards and retraction from the work, relatively rotatable elementsmounted on said tool and on said guiding .and supporting meansrespectively, said elements in engagement with each other and operativeon relative rotation to .eect movement of said tool along said guidingand supporting means, a motor for rotating one of said elements, andmeans for automatically imposing on said motor an additional load assaid tool approaches anend of its travel on said guiding'and supportingmeans, said load-imposing means including a tors-ion spring adapted tobe wound up and cooperating spring-Winding means and means governed bytool movement for effecting actuation of said spring-winding means bysaid motor-rotated element to effect Winding up of said spring as saidtool approaches said end of its travel.

11. In combination, a work-performing tool, guiding and supporting meansfor said tool, motor-operated feeding means for said tool including amotor-rotated element and an element with which said motor-rotatedelement is engaged, said elements so disposed and engaged in such mannerthat rotation of said motor-rotated elementV causes movement,longitudinally of said guiding and supporting means, of one of saidelements, said work-performing tool having said last mentioned elementconnected thereto so that such longitudinal movement of said element isattended by movement of said tool longitudinally of said guiding andsupporting means, and means Y for limiting travel of said tool in onedirection including a torsion spring coaxial with said m0- tor-rotatedelement and cooperating springwinding means actuated by saidmotor-rotated element for winding up said spring as'said limit of travelis approached.

12. In combination, a Work-performing tool, guiding and supporting meansfor said tool, motor-operated feeding means for said tool including amotor-rotated element and an element with which said motor-rotatedelement is -engaged, said elements so disposed and engaged in suchmanner that rotation of said motor-rotated element causes movement,longitudinally of said guiding and supporting means, of one of saidelements, said Work-performing tool having said last mentioned elementconnected thereto so that such longitudinal movement of said element isattended by movement ofV said tool longitudinally of said guiding andsupporting means, and means for limiting travel of said tool in onedirection including a torsion spring and cooperating springwinding meansactuated by said motor-rotated element for Winding up said spring toincrease the torsion of said spring automatically as said limit oftravel is approached.

13. In combination, a Work-performing tool, guiding and supporting meanstherefor along which said tool is adapted to be fed during feedingtowards and retraction from the Work, relatively rotatable elementsmounted on said tooi and on said guiding and supporting meansrespectively, said elements in engagement With each other and operativeon relative rotation to effect movement of said tool along said guidingand supporting means, a motor for rotating one of said elements, andmeans for automatically imposing on said motor an additional loadsuicient to stop tool movement as said tool approaches an end of itstravel on said guiding and supporting means, said load-imposing meansembodying rotary resistance means including rotary means actuated bysaid motor-rotated element, said rotary resistance means providingincreasing torsional resistance as said tool approaches its positionwherein it is stopped by said load-imposing means, said rotary meansbeing rotated by said motor-rotated element as said tool approaches saidposition thereby to increase the resistance to tool movement.

14. In combination, a Work-performing tool, guiding and supporting meanstherefor along .which said tool is adapted to be fed during feedingtowards and retraction from the Work, rela'- tively rotatable elementsmounted on said tool and on said guiding and supporting meansrespectively, said elements in engagement with each other and operativeon relative rotation to effect movement of said tool along said guidingand supporting means, a motor for rotating one of said elements, andmeans for automatically imposing on said motor an additional loadsuicient to stop tool movement as said tool approaches an end of itstravel on said guiding and supporting means, said load-imposing meansembodying rotary resistance means including means subjected to bothtorsion and axial compression and .cooperating rotary and axiallymovable means actuated for the application of torsional forces by saidmotor-rotated element for applying torsional and compression forces tosaid torsion and compression-subjected means and the latter providingunder each force increased resistance as said tool approaches itsposition wherein it is stopped by said load-imposing means, said rotaryand axially movable means being actuated by said motor-rotated elementas said tool approaches said position.

FRAN K E. SINCLAIR.

